Now, in addition to fire, explosion and suffocating gases, precautions must also be considered against possible chemical, biological, radiological and nuclear (CBRN) agents. To this end, the National Institute for Occupational Safety and Health (NIOSH) has established an optional certification program for SCBAs to be used in responding to attacks with these weapons of mass destruction (WMDs).

Since the certification guidelines were issued in January 2002, SCBA manufacturers have been working diligently to obtain CBRN certification. Some units have already been approved; others are still in process. Now that these products are commercially available or will be soon, industrial fire, safety and emergency response professionals will need to determine how much CBRN-certified SCBA equipment to purchase and deploy at specific locations.

CBRN Approval Process

The intent of certification is to ensure that CBRN agents will not permeate or penetrate components of an SCBA and enter the respiratory system of the user at what NIOSH and the U.S. Army Soldier and Biological Chemical Command (SBCCOM) consider to be maximum credible threat concentrations. Specifically, positive pressure, open-circuit SCBAs--less cylinder, but with all other integral components, and with whatever accessories the SCBA manufacturer designates for testing--must meet specified pass-fail criteria for penetration of mustard gas (HD) and Sarin (GB). These tests are run while the SCBA is operating on a breathing machine at a flow rate of 40 liters per minute for a 6-hour minimum service life.

In addition, a number of Laboratory Respirator Protection Level (LRPL) tests are also required, in which a panel of 25 test subjects wearing SCBA facepieces are exposed to an atmosphere containing 20-40 mg/m3 corn oil aerosol. The subjects are asked to perform a series of exercises. For the unit to pass, at least 24 of the 25 must achieve minimum LRPL levels of 500, equivalent to what is commonly known as a respirator protection factor, while the SCBA operates in a negative pressure mode.

These tests are in addition to existing NIOSH certification requirements for standard SCBA units as detailed in the performance requirements of 42 CFR Part 84, the special tests in 42 CFR Part 84.63(c), and certification of compliance to NFPA 1981, latest (2002) edition. Units that pass the certification tests will carry a NIOSH/CDC label in a visible location on the SCBA backplate, indicating that the apparatus is "CBRN Agent Approved."

Material Substitutions

To gain CBRN approval, at least some manu-facturers have found it necessary to substitute for materials that have been used in conventional SCBAs--in some cases for many years. The most troubling of these is silicone, the most comfortable, most durable, and best sealing facepiece skirt material for three decades.

Unfortunately, silicone cannot withstand the 6-hour NIOSH CBRN permeation test requirements. It will, however, stand up under two hours of exposure to HD and more than three hours to GB, offering reasonable one-time use protection for users of the longest duration open-circuit SCBA (rated by NIOSH at 60 minutes).

Other materials may also have to change, including high-impact plastics commonly used for second stage regulator housings and other components. Such changes could result in reduced durability of SCBA units.

Acquisition and Deployment

Fire safety and other officers at industrial sites must assess the level of risk associated with potential CBRN incidents and make decisions regarding SCBA acquisition and deployment accordingly. In areas that are at higher risk for a terrorist attack, a CBRN-certified SCBA may be the best choice for all or part of a plant's response gear. However, in low-risk areas, a CBRN-certified SCBA may be made available only as a backup or may not even be considered necessary.

Since there may be substantial changes required in materials for an SCBA to achieve CBRN certification, this could possibly result in diminished equipment durability and comfort for firefighting activities. Industrial sites should carefully consider the trade-offs for conventional use created by such changes.

Improving industrial site readiness for a WMD attack with CBRN-certified SCBAs does not have to be an all or nothing proposition. It would certainly be a good initial step to equip first responders trained for CBRN readiness with the new SCBAs. Then, over a number of months, it is possible to increase the availability of the CBRN-certified SCBAs by purchasing NIOSH-approved upgrade kits. These are already becoming commercially available.

Industrial fire safety officers should also understand that CBRN-certified SCBAs are not the total answer to protecting first responders to WMD attacks. For example, almost all chemical agents used by terrorists are absorbed through the skin as well as inspired into the respiratory system. Some agents are immediately fatal if an amount the size of the head of a pin comes in contact with a firefighter's skin. Therefore, when responding to a potential event involving chemical agents, effective dermal protection--in the form of an ensemble compliant with NFPA 1994--is essential. NIOSH recommends the following:Unknown hazards: Level 1 Fully Encapsulated Chemical Suit and CBRN SCBA.

The new NIOSH CBRN certification schedule for SCBAs is stringent, yet it is, of necessity, designed to meet circumstances that cannot be fully predicted. Furthermore, it is just part of the total program needed to protect responders from potential CBRN incidents. Because CBRN-certified SCBAs may not be as comfortable--or as rugged--as existing units, they may not be the most appropriate choice for conventional industrial fire fighting. Fire safety and plant security officers at individual industrial sites must assess the risk for terrorist activities and decide on a level of CBRN-certified equipment that should be inventoried and ultimately deployed in specific first response scenarios.